Bacteria Have Role in Swine Flu Deaths

Bacterial Infections Can Be Deadly for Some Patients With H1N1 Swine Flu

Medically Reviewed by Louise Chang, MD on September 30, 2009
From the WebMD Archives

Sept. 30, 2009 - Bacterial infections play a major role in H1N1 swine flu deaths, the CDC warns.

The swine flu bug can cause fatal pneumonia all by itself. But in a large number of cases it gets help from other deadly germs that take advantage of a weakened immune system and cause pneumonia.

A CDC investigation into 77 U.S. swine flu deaths found that 22 of the victims -- 29% -- suffered from at least one bacterial co-infection.

Ten of the 22 infections were caused by pneumococcus, an infection that can be prevented with either of two approved pneumococcal vaccines. The vaccine is recommended for any adult who has asthma or smokes, has a long-term health problem or immunity-lowering condition, or is over 65. It's routine for kids to get a four-dose series beginning at age 2 months.

Only 16% of the 18- to 49-year-olds who should get pneumococcal vaccine actually do so. The CDC is asking doctors to specifically target this population for vaccination this flu season.

Drug-resistant staph infection -- MRSA -- was involved in five of the deaths.

Earlier CDC reports found that H1N1 swine flu deaths tended to be caused by direct infection of the lungs with the new flu bug. That may have caused doctors to let down their guard against bacterial infections in flu patients.

That's a big mistake. Because very few bacterial infections can be detected with routine blood tests, the CDC now advises doctors who suspect bacterial infections in swine flu patients to treat them with anti-flu drugs andantibiotics.

When flu takes a turn for the worse, it's important to seek medical care right away. The CDC report carries dramatic examples of H1N1 swine flu deaths with bacterial infections:

  • A 2-month-old girl, with no known underlying condition, died with pneumococcal infection after an illness of only one day.
  • A 9-year-old girl with no reported underlying condition died with a strep infection after an illness of six days.
  • A 34-year-old man with high blood pressure and obesity died with pneumococcal infection after an illness of about three days.

For the 17 patients whose length of illness was known, illness ranged from one to 25 days with a median duration of six days.

Among the 22 patients who died of H1N1 swine flu with bacterial co-infection, ages ranged from 2 months to 56 years, with a median age of 31 years.

The CDC reports the findings in an early-release issue of Morbidity and Mortality Weekly Report.